The present invention refers to a suction muffler to be used in the refrigerant gas supply in a hermetic compressor for small refrigeration systems.
There are known in the art the suction mufflers constructed in injected plastic material and comprising, basically, a hollow body, which is provided, externally, with gas inlet and gas outlet nozzles and, internally, with a plurality of chambers and a duct having an end connected with and opened to the gas inlet nozzle of the hollow body, median windows, which are longitudinally spaced from each other and opened to respective chambers, and an opposite end opened to a last chamber, which is maintained opened to the gas outlet nozzle of the hollow body.
While conducting to a substantial noise attenuation, these prior art constructive solutions still allow noise to be produced in undesirable levels, which are even unacceptable in determined situations, as a function of a specific frequency that is developed in the last chamber which promotes the fluid communication between the duct, internally provided in the hollow body, and the gas outlet nozzle.
It is a general objective of the present invention to provide a suction muffler of the type considered herein, which allows to attenuate the noise produced in the last chamber of the hollow body, without however creating a complicating factor in the construction of the muffler or causing a relevant suction head loss.
The suction muffler of the present invention, comprising the basic elements mentioned above, allows the objective proposed herein to be achieved, by the fact that the last chamber is partially divided in two volumes with different shapes and sizes, by means of a deflecting wall occupying a substantial part of the height of the last chamber from a wall thereof opposite to that in which is provided the gas outlet nozzle, the opposite end of the duct projecting into the last chamber by an extension not greater than the height of the deflecting wall, both the gas outlet nozzle and the opposite end of the duct being opened to the larger volume of the last chamber, in opposite walls of the latter and in mutually offset positions. The construction defined above allows the acoustic mode developed in the last chamber to be attenuated, obtaining a shorter wavelength and a higher frequency, which becomes acoustically irrelevant. Thus, it is obtained a reduction in the level of the noise produced by the compressor.